The Discovery of the Chinese Grassbird 發現Chinese Grassbird

Rufous-rumped Grassbird has long confused ornithologists is Hong Kong, and recent research has shown that the population occurring in Hong Kong and south China should be treated as a separate species, Chinese Grassbird.

A population of large skulking warblers was first noted on Tai Mo Shan in the 1950’s and although originally thought to be a species of prinia, it later proved to be Large Grass Warbler, a species occurring from Hong Kong to Nepal. It was subsequently reclassified as a babbler, being quite unrelated to the warblers, and recently it has been found that the populations in the Indian subcontinent and in south-east Asia are better treated as different species.
Resolving the mystery of Hong Kong’s most enigmatic breeding bird required mist nets on Hong Kong's highest mountain, sound recordings in the terai grasslands of Nepal, examination of 100-year-old skins in museums in Germany and England, and DNA analysis of samples by Swedish biochemists.

Paul Leader, who led the international team of experts that finally put all the pieces together, will tell the whole story for the first time, and explain what must be done to protect Chinese Grassbird for future generations, and give you a reason to climb Hong Kong's highest mountain to look for one of its shyest and globally important birds!

Hong Kong-based ornithologist Paul Leader and an international team of experts have resolved a 30-year mystery to reveal the true identity of Chinese Grassbird, a globally threatened species which depends on protection of grasslands in Hong Kong for its continuing survival.

Requiring trapping with mist nets on Hong Kong's highest mountain, sound recordings in the terai grasslands of Nepal, examination of 100-year-old skins in museums in Germany and England, securing export permits for blood and feather specimens from Government officials during the avian influenza outbreak, and DNA analysis of samples by Swedish biochemists, the story reads like a cross between an Indiana Jones adventure and an episode of CSI.

“Assembling the evidence that has led to the identification of Chinese Grassbird as a full species has been an interesting challenge,” Paul Leader, Director of Asia Ecological Consultants, the ornithologist who led the work. “ But now we know how rare this bird is, the real work is ensure its survival. To do that we must protect and manage the grassland habitats it depends upon from the threats of development and reforestation.”

Resolving the mystery
The mystery began when a large skulking warbler, first noted on Tai Mo Shan in the 1950s, was thought to be Brown Prinia. However a bird mist-netted by David Melville former Executive Director of WWF (Hong Kong) in 1982 proved to be Large Grass Warbler, a species which occurs from Hong Kong to Nepal.

But in 2006 DNA analysis of Large Grass Warbler showed that it was not a warbler at all, but belonged to a completely different family – the babblers, and it was renamed Rufous-rumped Grassbird, as it was thought to be the same species as a very similar bird found in Nepal, India and Bangladesh.

It was only last month when the final part of the mystery was resolved. Mr Leader and his collaborators showed that birds from the Indian subcontinent, and southern China were in fact different by analysing the vocalisations, structure and plumage, and the DNA of birds from both locations. They have proposed that the two species should now be called Chinese

Grassbird and Indian Grassbird. Full details can be found in the newly released Forktail paper, which was co-authored by Mr Leader.

The history of Chinese Grassbird
First recorded in Hainan in 1892 by tea merchant and ornithologist Frederick Styan, and with a range that once extended to grasslands in Myanmar, Vietnam and Thailand, as well as Guangxi and Guangdong Provinces in China, Chinese Grassbird, has only twice been seen away from Hong Kong in the last 80 years.

The first of these records was from Shiwandashan in Guangxi in May 1997, and the second, in May 2001 was from Wutong Shan - the mountain that lies directly across the border from Robin’s Nest at the western end of the Frontier Closed Area. Curiously, both records were made by another Hong Kong ornithologist, Lee Kwok-shing, while conducting surveys for Kadoorie Farm & Botanic Garden.

The need for active conservation
Because it is found in low densities and difficult to detect – it rarely sings or calls – and is found mostly in remote mountainous areas, including Tai Mo Shan, Lantau Peak, and Robin’s Nest, the population of Chinese Grassbird is poorly known. Initial estimates suggest that there are no more that 50-100 pairs in Hong Kong – giving a maximum known global population of just 200 birds.

In Hong Kong Chinese Grassbird is found in low densities in grassland and dwarf bamboo habitats between 200 and 800 metres – and much of this habitat is protected within Hong Kong’s Country Parks. However, as Hong Kong continues to become greener and grassland becomes forest through a natural process called succession, the area of habitat available to this bird is shrinking steadily. In lowland areas outside the Country Parks, its habitat is also threatened by housing and infrastructure development.

As a result, in order to effectively protect the Chinese Grassbird, it is very important that sufficient grassland habitat is identified and actively managed to prevent further development and to prevent grasslands becoming forest (in which the birds cannot survive).

Mike Kilburn, Vice Chairman of Hong Kong Bird Watching Society called on the Hong Kong Government to take immediate steps to protect Chinese Grassbird and the habitat it depends on. This will require an accurate assessment of the current population, ecology and habitat requirements of the bird, as well as an assessment of the total area, quality and threats to its habitat. These would serve as essential steps in the development and the development and implementation of a species conservation plan that would ensure a secure future for Chinese Grassbird in Hong Kong.